An installation of this type is known from DE 24 54 091 A1. The installation has a process chamber with an inlet portal and an outlet portal, in which there is in each case one fluid stream curtain. The fluid stream curtain is in this case composed partially of fresh air, which can pass into the interior of the process chamber.
WO 2010/122121 A1 describes an installation for drying workpieces, which installation has a process chamber for controlling the temperature of workpieces, which process chamber is closed by means of a fluid stream curtain at an inlet portal and at an outlet portal. The process chamber is in this case likewise fed with the fresh air from the fluid stream curtain.
GB 2 123 936 A describes an installation for drying workpieces in a process chamber, which receives fresh air by means of a fluid stream curtain of the inlet portal and outlet portal.
U.S. Pat. No. 1,606,442 A has disclosed an installation for drying vehicle bodies, which installation has a process chamber which is separated from the surroundings by means of a fluid curtain. The vehicle bodies that are dried in the process chamber in the installation are moved through the fluid stream curtain as they exit the installation. To produce the fluid stream curtain, the installation has an aperture or nozzle with a slot-shaped opening which extends over the entire width of the process chamber.
U.S. Pat. No. 3,947,235 describes a process chamber and a method for drying freshly painted vehicle bodies, wherein a fluid stream curtain is produced between portals for the supply and discharge of the motor vehicle bodies into and out of the process chamber and a receiving region for the vehicle bodies in the process chamber.
In production units for painting and coating vehicle bodyworks, drying installations are used for drying vehicle bodyworks which have been freshly painted or coated with corrosion protection. Those installations have a process chamber which is in the form of a drying tunnel and into which hot air is blown. There is a drying zone in the drying tunnel. The drying zone is a receiving region for workpieces in the form of vehicle bodyworks. In order to dry the vehicle bodyworks, they are moved on a conveying device through the drying tunnel. The coat of paint or coating of the vehicle bodyworks to be dried may be impaired by impurities, in particular particles of dust. Furthermore, gaseous fluid and with it heat from the inner space may be discharged through a portal for the supply of workpieces.